High-pressure hydraulic pump



NOV.- 20, 1945. R LEVY HIGH PRESSURE HYDRAULIC PUMP Filed May 4, 1943 f E El/)f Patented Nov. 20, 1945 mon-PRESSURE HYDRAULIC PUMP Ren Lucien Levy, Paris, France, asslgnr to Societe d Inventions Aeronantiques et Mecanlques S. I. A. M., Geneva, Switzerland Application May 4, 1943, Serial No. 485,663

I 1n France May 9, 1941 1 Claim.

This invention relates to pumps and more particularly to improvements ln devices of this character designed to improve the efllciency thereof and to simplify their construction.

An embodiment of the pump according to the invention will now be described with reference to the accompanying drawing in which:

Fig- 1 is an axial section of the pump;

Fig. 2 is a section View, on a larger scale, of the part adjacent to one of the cylinders of the pump;

Fig. 3 is a section along line 3 3 of Fig. 1;

Fig. 4 is a section along line i-li of Fig. l;

Fig. 5 is a section along line 5-5 of Fig. 4.

The pump is constituted by a body l, preferably made of light metal, comprising parts 2 and 3 connected by bolts d. The upper part is of pentagonal prismatic form (Fig. 4) and the lower part, which is partly of the same form for its connection with the upper part, becomes of cylindrical form, and is provided with five wide hollow corrugations forming the iive cylinders i8 oi the barrel-pump. It is `to be understood that the number of cylinders may be different from five, and, the outer shape of the pump may be changed accordingly. Upper part 2 is united with a suitable support by means of threaded pins Si.

The pump presents a central shaft 6, which receives the power through toothed member l it is mounted in upper part 2 by a bearing il with conical rollers for withstanding axial thrust.

Shaft t is provided inside the pump with teeth i@ constituting a pinion meshing with a corresponding pinion il, the shaft l2 of which latter is located in body l. These two pinions constitute, together with inner partition i3 in body l, a gear pump of known type. Inlet port lli of this pump is provided in part 2 as also the outlet port it which ends in cavity l5, of semi-circular shape, and which latter is connected with the high pressure pump proper through holes il.

The high pressure pump, of the barrel type, is constituted by the cylinders i8 regularly distributed around the axis of said pump. The cylinders are fed from a common` chamber It, connected with cavity i6 through holes l'l. A ring 2t, integral with shaft 6, is disposed obliquely in reiation to the axis of said shaft. A cam 2l is,

on the other hand, disposed around tube 22 which surrounds the lower end of shaft 6. Between the cam 2l and ring 20 is provided a circular series of balls 23. The cam 2l is tted on tube 23 by means of spherical bearing 2t permitting the cam to undergo a rocking movement.

In each cylinder I8 is slidably mounted a piston 25, having an axial bore enlarged atits lower end to provide a shoulder forming al support for ring 2l.V In the top-end of said piston can slide a hollow cylindrical valve 29 which rests on ring 21 and is provided in its upper part with radial holes til. Head 3| of valve 29 isl engaged and opervated by cam 2l through balls 32 located in seats 33. Head 3l of the valve 29 may cooperate with the upper surface of head 28 of the piston, which surface constitutes a seat 3d. In cylinder i8 is a spring which rests at the one end on the bottom 36 of said cylinder, and, at the other end on ring 2l. The outlet 31 is bored in bottom 36 and is controlled by outlet valve 38 of conical shape and receives the action of spring 39 which rests on wall di) of circular channel lll. Circular channel il is connected with the outlet t3 through radial ports di and communicates through ports d2 with the outlets 3l when the valves 33 are open.

Chamber i9 of the barrel-pump and inlet pipe ld of gear-pump 'may be connected through an opening l5 the passage of which is controlled by a small ball fit subjected to the action of a spring di, of given strength guided by stem t8; so, the liquid can' ilow from chamber i8 back into inlet pipe it, but not in the opposite direction.-

The operation of this pump is as follows:

On account of the rotation of shaft t, the liquid contained in a tank (preferably at a higher level than the pump) is sucked through port ld of the gear pump. lllhe eiect of this pump is to put the liquid under a certain pressurel and to force it through port l5. So, the liquid which lls up chamber lll of the barrel-pump is placed under a predetermined pressure. When the said pressure in chamber I9 rises above a pre-determined value, ball t6 is lifted up and the liquid is by-passed to the port it.

By rotation of shaft 5, barrel-pump is put into action, pistons 25 being moved downwardly in succession by the camming action of the cam 2 l. Just the admission valve 29 is pressed downwardly against the tension of the spring 35, the piston 25 remaining motionless on account of the friction of said piston against the inner wall of cylinder i8. By this movement, 'the valve 29 is brought on its seat all and isolates the corresponding cylinder from chamber i9. The piston 25 is then pushed down; the liquid in the cylinder is put under pressure and, when the pressure for discharge is reached, valve 38 opens and liquid escapes through ports 3l and d2, circular channel el and ports M to the outlet opening it. At the end o! the working stroke. the valve Il closes and valve 28 is opened by the spring l5, the piston 25 remaining motionless momentarily owing to its friction against the inner wall of cylinder. v .being greater than friction of valve 2l in piston movement of piston 25 under the action of spring I5, the admission of liquid to the cylinder is ef- 1 fected.

I claim: A high pressure pump comprising atleast one cylinder, a piston slidable in said cylinder and v2 zeeman.

including a hollow body and a head formed with a bore, a ring siidable in said bore, an internal shoulder in said bore forming a stop for said ring, ythe terminal oi' said bore at the end of the piston head constituting a valve seat, an inlet valve engageable with said seat and havinga hollow stem slidable in said bore and abutting said ring, the portion oi' the stem adjacent said valve having a radial port therein, a spring tending to move the ring in one direction against the shoulder and thereby open said valve and actuate the piston. and means for closing the valve and moving the piston in the opposite direction.

' LUCIEN LEVY. 

